Collimated optical system

ABSTRACT

An optical system provides a lens cell having a generally cylindrical lens cell body and an optical lens system therein. The lens cell body has a lens cell central longitudinal axis and a lens cell optical axis, eccentrically offset from the lens cell central longitudinal axis. A sleeve has a generally cylindrical sleeve body, an outer surface with a first longitudinal axis, and an inner surface with a second longitudinal axis, eccentrically offset from the first longitudinal axis. The lens cell is inserted into the sleeve. A housing has a generally cylindrical body into which the sleeve is at least partially inserted. The lens cell and the sleeve are rotated relative to each other and to the housing such that the lens cell optical axis is aligned in a desired location. After the lens cell optical axis is aligned in the desired location, the lens cell is fixedly connected to the sleeve and the sleeve is connected to the housing to prevent rotation of the sleeve relative to the housing.

CROSS REFERENCE TO RELATED APPLICATIONS

It is hereby stated and incorporated by reference, this application is aDivisional of U.S. patent application Ser. No. 11/268,784, filed on Nov.8, 2005.

BACKGROUND OF THE INVENTION

In a vision-assisting device, such as a monocular, the device iscollimated when the output optical axis matches the input optical axissuch that the beam of light entering the device is parallel with thebeam of light exiting the device. Typical assembly procedures produce adevice that is not collimated due to inconsistencies in the mounting ofvarious optical elements within the device. A night vision devicenormally deviates from a collimated system due to the offset caused bythe microchannel plate and twisted fiber optic within the device.

When the device is not collimated, the image produced by the system isslightly out of alignment with the input image. Such slight misalignmentis typically not a problem for a monocular. However, a binocularconstructed from two uncollimated monoculars results in a user's eyesneeding to independently point in different directions. This is a veryunnatural condition, and often causes the user to experience eyestrainand headaches.

The F5050 night vision goggle collimates one monocular to the otherthrough the use of a mechanism that includes a single eccentricmechanical housing. The single eccentric housing allows shifting of theoptical image to approximate a collimated image. However, the F5050goggles must be aligned as a system. Neither output optical axis isnecessarily aligned with the mechanical axis of the binocular, or theinput optical axes. If one of the monoculars is replaced or serviced,then both monoculars again need to be collimated to make the output axesparallel.

It would be beneficial to provide a collimated binocular in which amonocular can be replaced or serviced without having to re-collimateboth monoculars in the binocular.

SUMMARY OF THE INVENTION

Briefly, the present invention provides an optical system comprising alens cell having a generally cylindrical lens cell body and an opticallens system therein. The lens cell body has a lens cell centrallongitudinal axis and a lens cell optical axis, eccentrically offsetfrom the lens cell central longitudinal axis. A sleeve has a generallycylindrical sleeve body, an outer surface with a first longitudinalaxis, and an inner surface with a second longitudinal axis,eccentrically offset from the first longitudinal axis. The lens cell isinserted into the sleeve. A housing has a generally cylindrical bodyinto which the sleeve is at least partially inserted. The lens cell andthe sleeve are rotated relative to each other and to the housing suchthat the lens cell optical axis is aligned in a desired location. Afterthe lens cell optical axis is aligned in the desired location, the lenscell is fixedly connected to the sleeve and the sleeve is connected tothe housing to prevent rotation of the sleeve relative to the housing.

Additionally, the present invention further provides a binocularcomprising a frame, a first monocular including the optical system asdescribed above, and a second monocular having the same configuration asthe first monocular. The first and second monoculars are separatelyreleasably connected to the frame.

Also, the present invention provides a method of manufacturing acollimated optical device comprising the steps of providing the elementsof the optical system as described above; inserting the lens cell intothe sleeve; inserting the sleeve at least partially into a housing,wherein the housing comprises a generally cylindrical housing body;independently rotating the sleeve and the lens cell relative to eachother and to the housing until the optical device is at a desiredcollimation; securing the sleeve and the lens cell to each other toprevent rotation of the sleeve relative to the lens cell; and securingthe sleeve to the housing to prevent rotation of the sleeve relative tothe housing.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed descriptionpreferred embodiments of the invention, will be better understood whenread in conjunction with the appended drawings, which are incorporatedherein and constitute part of this specification. For the purposes ofillustrating the invention, there are shown in the drawings embodimentsthat are presently preferred. It should be understood, however, that theinvention is not limited to the precise arrangements andinstrumentalities shown. In the drawings, the same reference numeralsare employed for designating the same elements throughout the severalfigures. In the drawings:

FIG. 1 is a perspective view of a binocular including a monocularaccording to an embodiment of the present invention;

FIG. 2 is a perspective view of the monocular only according to anembodiment of the present invention;

FIG. 3 is a longitudinal side view, in section, of the monocular shownin FIG. 1;

FIG. 4 is an exploded view of eyepiece components of the monocular shownin FIG. 1;

FIG. 5 is an enlarged view of a portion of the eyepiece portion shown inFIG. 3;

FIG. 6 is a perspective view of a connection between a housing andsleeve of the eyepiece shown in FIG. 4;

FIG. 7 is a profile view from an output end of the sleeve shown in FIG.4;

FIG. 8 is a perspective view of a lens cell being inserted into thesleeve; and

FIG. 9 is a profile view from an output end of the lens cell.

DETAILED DESCRIPTION OF THE INVENTION

Certain terminology is used herein for convenience only and is not to betaken as a limitation on the present invention. The terminology includesthe words specifically mentioned, derivatives thereof and words ofsimilar import. As used herein, the term “input” is defined to mean adirection farther from a user when the monocular is in a use position asdescribed herein and “output” is defined to mean a direction closer tothe user when the monocular is in a use position as described herein.The following describes a preferred embodiment of the invention.However, it should be understood based on this disclosure, that theinvention is not limited by the preferred embodiment of the invention.

Referring to the drawings generally, a monocular 100 according to apreferred embodiment of the present invention is shown. The preferredmonocular 100 can be used as a monocular or can be part of a nightvision goggle (NVG) binocular 210, shown in FIG. 1. These devices areused to intensify ambient or infrared light for enhanced visibility in adarkened environment.

Referring to FIG. 2, the monocular 100 is generally tubularly shaped,with an input end 102, which receives light from the externalenvironment, and an output end 104, which transmits the intensifiedimage to a user. Referring to FIG. 3, which is a longitudinal sectionview of the monocular 100, the major components of the monocular 100are, from left to right, an eyepiece 106, an image intensifier tube 190and an objective objective lens assembly 192, which are all carried in ahousing 110.

Referring to FIGS. 3-5, the eyepiece 106 includes a lens cell 150disposed within the sleeve 130, which is partially disposed within thehousing 110. A focus ring 170 threadably engages the housing 110 and isoperative to longitudinally translate the sleeve 130 and the lens cell150 with respect to the housing 110. Such translation is preferablyaccomplished without rotating the sleeve 130 and the lens cell 150 withrespect to the housing 110. The eyepiece 106 is collimated duringfabrication. Therefore, it is desired that the sleeve 130 and the lenscell 150 do not rotate relative to the housing 110 or each other duringoperation, such as during focusing of the eyepiece 106 by the user.

The housing 110 is in the form of a generally tubular body 112. Anoutput end 114 of the housing 110 include two diametrically spacedelongated slots 116 formed in the body 112. The slots 116 are sized toallow a shoulder pin 118, shown in FIG. 6, to be inserted therethroughto engage the eccentric sleeve 130, as will be described later in detailherein. The shoulder pin 118 includes a preferably square head 118 athat fits into the slot 116 and a cylindrical shank 118 b extendingtherefrom and into the sleeve 130. Preferably, the head 118 a does notextend beyond the exterior of the body 112 in the area of the shoulderpin 118. While the shoulder pin 118 is preferred, those skilled in theart will recognize that a set screw or other known securing device maybe used instead of the shoulder pin 118.

Referring back to FIGS. 3-5, the housing 110 also includes a thread 120formed on the outer surface of the body 112 to threadably engage thefocus ring 170. At the input end 102, the housing 110 includes aplurality of circumferentially spaced ridges 122 that extend generallyparallel to each other and longitudinally along the length of the inputend 102. The ridges 122 assist the user in gripping the monocular 100during use.

The eccentric sleeve 130 includes a generally cylindrical body definedby an outer surface 132 having an outer cylinder axis 134 that extendsperpendicularly out of the plane of the page of FIG. 7, and an innersurface 136 that is eccentrically offset from the outer surface 132. Theinner surface 136 has an inner cylinder axis 138 that extendsperpendicularly out of the plane of the page of FIG. 7. The innercylinder axis 138 is slightly offset from the outer cylinder axis 134 bya slight distance, preferably approximately 0.5 millimeters, althoughthose skilled in the art will recognize that the offset distance may bemore or less than 0.5 millimeters. This offset creates a firsteccentricity in the sleeve 130 such that, when the sleeve 130 isinserted into the housing 110 and rotated within the housing 110 duringfabrication, the inner cylinder axis 138 shifts relative to the outercylinder axis 134.

Referring to FIG. 8, the sleeve 130 also includes a series of recesses140 that are circumferentially spaced about the outer surface 132. Inthe preferred embodiment, 40 recesses 140 extend, evenly spaced, aroundthe outer surface 132. The recesses 140 may, but not necessarily, extendthrough the outer surface 132 to the inner surface 136. The recesses 140are sized to accept and retain the cylindrical shank 118 b with a snugfit. As shown in FIG. 6, when the sleeve 130 is inserted into thehousing 110, the sleeve 130 is aligned with the housing 110 such that aselected one of the recesses 140 is aligned with the elongated slot 116.The shoulder pin 118 is insertable through the elongated slot 116 sothat the cylindrical shank 118 b is inserted into the selected recess140 and the head 118 a is seated in the elongated slot 116. The shoulderpin 118 prevents the sleeve 130 from rotating relative to the housing110, but the elongated slot 116 allows the shoulder pin 118 and thesleeve 130 to translate longitudinally relative to the housing 110.

Referring back to FIG. 8, the outer surface 132 includes a groove 141that extends circumferentially around an output end of the sleeve 130.The groove 141 is sized to accept and retain an o-ring to seal a jointbetween the outer surface 132 and the housing 110 during assembly of themonocular 100. The outer surface 132 also includes a lip 142 thatextends radially outwardly away from the outer surface 132 between thegroove 141 and the recesses 140. The lip 142 engages the focus ring 170such that rotation of the focus ring 170 longitudinally translates thesleeve 130 relative to the housing 110.

The outer surface 132 further includes a groove 143 that extendscircumferentially around an input end of the sleeve 130. The groove 143is sized to accept and retain a snap ring inserted therein. The snapring secures the focus ring 170 against the lip 142, as can be seen inFIG. 5.

Referring back to FIG. 8, the inner surface 136 also includes aplurality of teeth 144 that extend radially around an input lip 146 thatextends inwardly from the inner surface 136 toward the inner cylinderaxis 138. The plurality of teeth 144 engage a plurality of mating teethon the lens cell 150, as will be described in detail later herein.

Referring to FIG. 5, the inner surface 136 also includes an internalthread 147 that receives a locking ring 148. The locking ring 148 biasesthe lens cell 150 against the sleeve 130 and transmits longitudinalmotion of the sleeve 130 to the lens cell 150 during focusing. Thelocking ring 148 includes an external thread 149 that engages theinternal thread 147 of the inner surface 136. The output end of thelocking ring 148 also includes a pair of diametrically opposed slots 149a, shown in FIG. 4, that are used to insert the locking ring 148 intothe sleeve 130. An insertion tool (not shown) engages the slots 149 a.The insertion tool is rotated, thus rotating the locking ring 148 andthreading the locking ring 148 onto the sleeve 130.

The lens cell 150 includes a generally cylindrical body defined by anouter surface 152 having an outer cylinder axis 154 that extendsperpendicularly out of the plane of the page of FIG. 9, and an innersurface 156 that is eccentrically offset from the outer surface 152. Theinner surface 156 has an optical axis 158 that extends perpendicularlyout of the plane of the page of FIG. 9. The optical axis 158 is slightlyoffset from the outer cylinder axis 154 by a slight distance, preferablyapproximately 0.5 millimeters, although those skilled in the art willrecognize that the offset distance may be more or less than 0.5millimeters. This offset creates a second eccentricity in the lens cell150 such that, when the lens cell 150 is inserted into the sleeve 130and rotated within the sleeve 130 during fabrication, the optical axis158 shifts relative to the outer cylinder axis 154.

Referring back to FIG. 3, the lens cell 150 includes a plurality oflenses 160 disposed within the inner surface 156. The lenses 160 includecentral axes 162 that are all aligned with the optical axis 158.Combined with the first eccentricity in the sleeve 130, the optical axis158 can be manipulated about the outer cylinder axes 134, 154 until theoptical axis 158 is collimated with the rest of the monocular 100.

Referring now to FIG. 8, the outer surface 152 includes a groove 161that extends circumferentially around an input end of the lens cell 150.The groove 161 is sized to accept and retain an o-ring to seal a jointbetween the outer surface 152 and the sleeve 130 during assembly of themonocular 100. A portion of the input end of the lens cell 150 alsoincludes a plurality of mating teeth 164 that engage the teeth 144 onthe sleeve 130. The teeth 164 are preferably arranged in three sets thatare circumferentially arranged around the input end of the lens cell150. However, those skilled in the art will recognize that more or lessthan three sets of teeth 164 may be spaced around the input end of thelens cell 150. A lip 166 extends longitudinally away from the input end.The lip 166 includes a plurality of cutouts 167, with each cutout 167spaced adjacent a set of the teeth 164. The cutouts 167 are formed toassist in cutting the teeth 164 during manufacture.

Referring back to FIG. 4, the output end of the lens cell 150 alsoincludes a pair of diametrically opposed slots 168 formed therein. Theslots 168 are sized to accept an insertion tool (not shown) to assist ininserting the lens cell 150 into the sleeve 130 during assembly. Agroove 169 is formed in the outer surface 152 between the groove 161 andthe teeth 164. The groove 169 is sized to accept and retain an o-ring toseal a joint between the outer surface 152 and the sleeve 130 duringassembly of the monocular 100.

The focus ring 170 includes a generally annular body defined by an outersurface 172 and an inner surface 174. The outer surface 172 includes aplurality of circumferentially spaced longitudinal grooves 176. Thegrooves 176 enable a user to grip the focus ring 170 and rotate thefocus ring 170 to focus the eyepiece 106 during use.

The inner surface 174 includes a threaded formation 178 that engages theexternal thread 120 on the housing 110. The inner surface 174 alsoincludes a groove 180 that is sized to accept and retain an o-ring toseal a joint between the inner surface 174 and the sleeve 130.Additionally, referring to FIG. 5, the inner surface 174 includes a lip182 that extends toward the sleeve 130 and engages the lip 142 of thesleeve 130.

A snap ring 184 is used to secure the focus ring 170 against the sleeve130. The snap ring 184 snaps into the groove 143 in the sleeve 130 andsecures the lip 182 of the focus ring 170 against the lip 143 of thesleeve 130.

Referring back to FIG. 3, the image intensifier 190 is located withinthe housing 110 and includes all of the optics, electronics andassociated devices to operate the image intensifier 190. The objectivelens assembly 192 is located within the housing 110, between the imageintensifier 190 and the input end 102. The image intensifier 190 and theobjective lens assembly 192 can be any known apparatus and need not bedescribed in detail. However, while FIG. 3 shows multiple lensescomprising the objective lens assembly 192, those skilled in the artwill recognize that the objective lens assembly 192 may include a singlelens only. A power connector 194 extends outwardly from the housing body112. The power connector 194 electrically connects the image intensifier190 to a power source (not shown). The power connecter 194 alsoreleasably physically connects the monocular 100 to a support, such asfor binoculars or a weapon sight.

A plurality of o-rings 196 are used in the monocular 100 to sealengagement surfaces of several of the above-referenced components tokeep moisture and dirt from entering the internal structure of themonocular 100.

To assemble the eyepiece 106, the image intensifier 190 and theobjective lens assembly 192 are inserted into the monocular 100according to known methods. The lens cell 150 is partially inserted intothe sleeve 130 as shown in FIG. 8 so that the mating teeth 164 of thelens cell 150 engage the teeth 144 of the sleeve 130. The combinedsleeve 130 and lens cell 150 are then inserted into the housing 110. Thesleeve 130 and the lens cell 150 are independently rotated relative toeach other and to the housing 110 in order to collimate the monocular100. The eccentricity of the optical axis 158 with respect to the outercylinder axis 154 of the lens cell 150, as well as the eccentricity ofthe outer cylinder axis 134 relative to the inner cylinder axis 138 ofthe sleeve 130, allows the sleeve 130 and the lens cell 150 to berotated relative to the housing 110 until the optical axis 158 iscollimated with the image intensifier 190 and the objective lensassembly 192. The teeth 144 and the mating teeth 164 are ramped to allowindexing during collimation. In the event that the teeth 164, 144 do notperfectly align to retain perfect collimation, the lens cell 150 may beindexed relative to the sleeve 130 to obtain a mating engagement betweenthe teeth 164, 144, while only slightly distorting the collimation ofthe eyepiece 106.

Next, the sleeve 130 is aligned with the housing 110 such that aselected recess 140 is aligned with each elongated slot 116. When arecess 140 is aligned with one of the slots 116, another recess 140 willbe aligned with the remaining slot 116. A shoulder pin 118 is insertedthrough each slot 116 such that the cylindrical shank 118 b is insertedinto the selected recess 140 and the head 118 a is inserted into theslot 116. The shoulder pins 118 prevent rotation of the sleeve 130 andlens cell 150 relative to the housing 110, and also restrictlongitudinal translation of the sleeve 130 with respect to the housing110 since the shoulder pins 118 are limited in translation to the lengthof the slots 116. In the event that the recesses 140 and the slot 116 donot perfectly align to retain perfect collimation, the sleeve 130 may beindexed relative to the housing 110 to obtain alignment between therecesses 140 and the slots 116, while only slightly distorting thecollimation of the eyepiece 106. Once the optical axis 158 iscollimated, the lock ring 148 is threaded onto the sleeve 130 to securethe lens cell 150 against the sleeve 130.

The focus ring 170 is next threaded onto the housing 110. The snap ring184 is snapped into the groove 143 and secures the lip 182 of the focusring 170 against the lip 142 of the sleeve 130 so that translation ofthe focus ring 170 caused by the threaded connection of the focus ring170 with the housing 110 is transferred to the sleeve 130 and the lenscell 150 without rotation of the sleeve 130 or the lens cell 150.

The monocular 100 may be part of a helmet-mounted or handheld nightvision system. Alternatively, the monocular 100 may be used as a sightfor a weapon system, such as a rifle or even a tank. Further, themonocular 100 may be incorporated into any optical system requiringfocusing and collimation.

Referring back to FIG. 1, a second monocular 200 is used in conjunctionwith the monocular 100 to form the binocular 210. The second monocular200 is preferably structurally similar to the monocular 100. The firstand second monoculars 100, 200 are releasably connected to a binocularframe 212 through the power connector 194 on each monocular 100, 200. Inthe event that one of the monoculars 100, 200 needs to be repaired orreplaced, that monocular is removed from the frame 212 and repaired orreplaced. When the repaired or replacement monocular is connected to thebinocular frame 212, the repaired or replaced monocular does not need tobe collimated with the original monocular.

Although the invention is illustrated and described herein withreference to a specific embodiment, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention. While preferred embodiments ofthe invention have been shown and described herein, it will beunderstood that such embodiments are provided by way of example only.Numerous variations, changes and substitutions will occur to thoseskilled in the art without departing from the spirit of the invention.Accordingly, it is intended that the appended claims cover all suchvariations as fall within the spirit and scope of the invention.

1. A binocular comprising: a frame; a first monocular including: a lenscell having a generally cylindrical lens cell body and an optical lenssystem therein, wherein the lens cell body has a lens cell centrallongitudinal axis and a lens cell optical axis, offset from the lenscell central longitudinal axis; a sleeve having a generally cylindricalsleeve body, wherein the sleeve body has an outer surface with a firstlongitudinal axis and an inner surface with a second longitudinal axisoffset from the first longitudinal axis, wherein the lens cell isinserted into the sleeve; and a housing having a generally cylindricalhousing body, wherein the sleeve is at least partially inserted into thehousing, wherein the lens cell and the sleeve are rotated relative toeach other and to the housing such that the lens cell optical axis isaligned in a desired location, and wherein, after the lens cell opticalaxis is aligned in the desired location, the lens cell is fixedlyconnected to the sleeve and the sleeve is connected to the housing toprevent rotation of the sleeve relative to the housing; and a secondmonocular having the same configuration as the first monocular, whereinthe first and second monoculars are separately releasably connected tothe frame.
 2. The binocular according to claim 1, wherein the lens cellbody comprises a plurality of locking members and wherein the sleevebody comprises a plurality of mating members engaged with the pluralityof locking members to prevent rotation of the lens cell relative to thesleeve.
 3. The binocular according to claim 1, wherein the outer surfaceof the sleeve body comprises a plurality of recesses circumferentiallyspaced therearound and wherein the eyepiece further comprises at leastone locking member extending through the housing and into one of theplurality of recesses to connect the housing and the sleeve together. 4.The binocular according to claim 3, wherein the housing comprises atleast one elongated opening therein, and wherein each of the at leastone locking member extends through a complementary one of the at leastone elongated opening.
 5. The binocular according to claim 4 wherein theplurality of recesses may be indexed relative to the at least oneelongated opening.
 6. The binocular according to claim 1, wherein thesleeve is longitudinally translatable relative to the housing.
 7. Thebinocular according to claim 1, further comprising a focus ringthreadably connected to the housing.